Angiogenesis: a potential target for therapy of soft tissue sarcomas

Combined vascular endothelial growth factor receptor/epidermal growth factor receptor blockade with chemotherapy for treatment of local, uterine, and metastatic soft tissue sarcoma

PURPOSE

Soft tissue sarcoma (STS) is a rare heterogeneous malignancy. Overall survival has been stagnant for decades, primarily because systemic therapies are ineffective versus metastases, the leading cause of STS lethality. Consequently, we examined whether tyrosine kinase receptors active in STS growth signaling might be blockable and whether multireceptor blockade might synergize with low-dose STS chemotherapy by therapeutically affecting STS cells and their associated microenvironment.

EXPERIMENTAL DESIGN

Vandetanib (AstraZenca), a tyrosine kinase inhibitor of vascular endothelial growth factor receptor 2 and epidermal growth factor receptor, was evaluated alone and with chemotherapy in vitro and in vivo in three human STS nude mouse xenograft models of different STS locations (muscle, uterus, lung), stages (primary, metastatic), and subtypes (leiomyosarcoma, fibrosarcoma, uterine sarcoma: luciferase-expressing MES-SA human uterine sarcoma cells surgically implanted into uterine muscularis with bioluminescence tumor growth assessment; developed by us).

RESULTS

In vitro, human STS cells were sensitive to vandetanib. Vandetanib alone and with chemotherapy statistically significantly inhibited leiomyosarcoma local growth and fibrosarcoma lung metastasis. Direct injection of MES-SA into nude mice uterine muscularis resulted in high tumor take (88%), whereas s.c. injection resulted in no growth, suggesting microenvironmental tumor growth modulation. Vandetanib alone and with chemotherapy statistically significantly inhibited uterine sarcoma growth. In all models, vandetanib induced increased apoptosis, decreased tumor cell proliferation, and decreased angiogenesis.

CONCLUSIONS

Vandetanib has antitumor effects against human STS subtypes in vitro and in vivo, where it also affects the tumor-associated microenvironment. Given the urgent need for better systemic approaches to STS, clinical trials evaluating vandetanib, perhaps with low-dose chemotherapy, seem warranted.

Novel treatment strategies for soft tissue sarcoma

Soft tissue sarcoma is a heterogeneous group of rare tumours arising predominantly from the embryonic mesoderm. While the prognosis is excellent for patients diagnosed at an early stage and treated by adequate surgery, unresectable or advanced metastatic diseases shrink the overall survival at 5 years dramatically to less than 10%. For metastatic soft tissue sarcoma, the armamentarium of effective chemotherapeutic agents is limited, especially when patients failed anthracycline- and/or ifosfamide-based chemotherapy. Fortunately, progress in the understanding of molecular biology and pathogenesis of soft tissue sarcomas has been made recently and should in the near future translate into molecular tumour characterization and the development of new therapeutic strategies. In this review, we briefly describe the status of current treatment strategies for soft tissue sarcoma. We will focus on the new and emerging compounds including recent developments of targeted therapy and cytotoxics such as antiangiogenic and immunomodulatory drugs, Bcl-2 antisense therapy, raf kinase inhibitors, heat shock protein modulators, anti-cytotoxic T lymphocyte-associated antigen (CTLA)-4 monoclonal antibody, proteasome inhibitors, minor groove binders, topoisomerase I inhibitors, and other agents being extensively developed in these solid tumours.